Field of the Invention
The present invention relates generally to seed planting implements, and in particular, to an improved mounting structure for mounting gauge wheel arms and closing wheel arms to a seed planting implement.
Description of the Related Art
In approximately 1974 John Deere introduced its Max Emerge Model 7000 planter, which included gauge wheels that carry the weight of the row unit, and gauge wheel arms that supported the offset loads of the gauge wheels. Because of the way the offset loads are supported by the gauge wheel arms, the durability of the gauge wheel arms and their pivot mounting was poor. The ground load on the gauge wheel is offset from the center of the row where the arm pivots upward and engages an adjustable stop.
Because of the offset load the arm is always trying to lean sideways. The load then is supported by two points of contact between the pivot pin and the bore of the hub. One point is on top of the pin at the inner end of the hub, and the other point is on the bottom of the pin at the outer end. These two points of contact are small and highly loaded. Because of the oscillating motion, grease gets squeezed out of these two points of contact and does not get carried back into them.
As a result the two points of contact are bound to wear. As they wear the arm leans allowing the tire to pull away from the opener disk. This eventually allows moist soil sticking to the disk to be carried up into the space between the wheel and opener disk. A scraper removes the soil from the disk which then can accumulate and plug this space. The same plugging can occur with trash.
In 1994, the Applicant introduced a gauge wheel arm mounting assembly that used a disc spring (Belleville Washer) to support the offset load. This gauge wheel arm mounting assembly is illustrated in FIGS. 5, 6 and 7 of Applicant's U.S. Pat. No. 5,904,107. Shims were used to set the spring pressure.
After one year it was apparent that a simpler method of adjusting the spring pressure was needed. A threaded adjustment was then developed by the Applicant, which is shown in FIGS. 8 and 9 of U.S. Pat. No. 5,904,107. This threaded adjustment later evolved into an attaching method shown in Applicant's Instruction Sheet AI-1250. Item K in instruction sheet AI-1250 is an adjusting stud assembly. The adjusting stud is machined from bar stock and has a tapped hole. The attaching stud is a threaded stud screwed into the tapped hole. The attaching stud is fixed within the adjusting stud using, for example, a thread adhesive compound. The attaching stud is screwed into the tapped hole in the end of the fixed pivot pin (not shown).
Disc spring pressure is adjusted by a nylon insert locknut J. Properly installed a force of approximately 1500 lbs. is applied to the ends of the hub. This is more than required to prevent the arm from leaning but it can still pivot freely. Because the arm cannot lean the pressure on the ends of the hub is evenly distributed around the circle of contact which is a big area. This results in the wear almost being eliminated. The result is that the tire can be adjusted to stay in contact with the opener disk indefinitely. Adjusting washers at each end of the hub are used to establish the proper relationship between the tire and opener disk.
In 1997, the John Deere Model 1700 planter model was introduced. The gauge wheel arm pivot incorporated a threaded bushing which allowed the arm to be moved in or out simply by loosening a bolt and turning the threaded bushing. No adjusting washers are needed. This gauge wheel arm pivot assembly is illustrated in FIGS. 2 and 3 of U.S. Pat. No. 5,427,038.
To use the RKP gauge wheel arm pivot kit with the Model 1700 planter, it was necessary to replace the threaded bushing with a split bushing F, as illustrated in Applicant's Instruction Sheet AI-1251.
In 2014, the John Deere Model MaxEmerge 5 (ME5) planter row unit was introduced, which included a redesigned gauge wheel arm. The redesigned gauge wheel arm still provides a threaded feature for adjusting the position of the gauge wheels. It also has a bearing surface at each end of the bore of the hub. The gauge wheel arm mounting assembly for the Model ME5 planter is illustrated in FIGS. 2 and 3 of U.S. Pat. No. 8,387,715.
In 1998, the disc spring design used on planter gauge wheel arm pivots was adapted to the early John Deere Model 750 no-till drills, as shown on Applicant's Instruction Sheet AI-1240. This drill did not have sleeve bearings and it was very impractical to try to repair it. The problem of wear on the pivot was very similar to that of the planter gauge wheel arm pivot.
The Applicant's disc spring design was successfully used in the Model 750 drills, and was later adapted to the other model drills, as shown in Applicant's Instruction Sheet AI-1242.
However, there is still a need for an improved mounting structure for mounting a pivot arm, such as a gauge wheel arm or a closing wheel arm, to an implement.